h the pawn (or the d-pawn hangs), weakening his king's position.
Smith continues (after 10...Be7) with 11. Rac1, Ne5;
12. Nxe5, dxe5 (12...Qxe5; 13. f4, Qc5+; 14. Kh1 and White has a winning game), 13. Bd2 with more than enough for the pawn.
11. Bb3
After 11. Rac1, Nde5; 12. Nxe5, Nxe5; 13. Nd5?! exd5; 14. exd5, f6! 15. Bd2, Qd8; 16. f4, Bg4; 17. Qe4, Bxd1; 18. fxe5, fxe5; 19. Rxd1, Be7; 20.Rf1, Rf6; 21. Bd3 (Frankle-Brill, Atlantic Open, NY, 1973), Qd7; White does not have sufficient compensation for his sacrificed mateial.
11...Nde5; 12. Nxe5, Nxe5; 13. f4!? h6! 14. Bh4
Black is attaining the strategic goals of his innovation. He has already traded off a pair of knights without, as in Smith's line, getting doubled pawns. He has prevented the board from opening up so that White hasn't been able to capitalize on his lead in development and develop an attack.
Now, after driving away White's black-squared bishop, Black intends to complete his development and castle, remaining a pawn up.
14. fxe5? hxg5; gives black the open h-file, e.g., 15. exd6, Qe5; 16. g3, Bxd6 with a positional and material superiority for Black.
14... Ng6; 15. Bg3, Be7; 16. f5, Ne5; 17. Rac1
17. fxe6, Bxe6; 18. Bxe6, fxe6; 19. Qh5+, g6; 20. Qh3, Kf7! leads to a won endgame for Black.
17...0-0; 18. Qh5?! ef5! 19. Nd5
White goes down fighting. If 19. exf5, Bg5 and 20...Bxf5 wins.
19...Bg5; 20. Rc7, f4!
Winning the bishop due to the threat of 21...Bg4, trapping the Queen.
21. h3, fxg3; White resigns.